Terminal for incandescing conductors.



APPLICATION FILED .TULYZ, 1906.

Patented July 18, 1911.

WNW/E5555 UNITED STATES PATENT OFFICE.

AXEL O. APPEL BEBG, OF SCHENECTADY, NEW YORK, ASSIGNOR '10 GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

TERMINAL FOR INCANDESCING CONDUC'JEORS.

Specification of Letters Patent.

Patented July 18, 1911.

Application filed July 2, 1906. Serial No. 824,890.

new and useful Im rovements in Terminals for Incandescing onductors, ofwhich the following is a specification.

This invention relates to terminals or supports for refractory metalconductors and comprises a novel arrangement of such conductors andsupports.

It also comprlses (as applicable to such an arrangement and for otherpurposes) ure metal terminals pressed or molded om powdered material andused to hold a filament of a lamp or a heater of a furnace, or used inany type of electrical apparatus Where an incandescing conductor must bemaintained in a predetermined position while hot.

The terminal may consist of the same metal as the incandescing conductoror of some metal which does not chemically react therewith and which issuitably refractory at the temperature at which the conductor operates.

My invention is applicable to pressed or molded terminals of variousmetals as applied to incandescing conductors of the same or othermetals, but in order that my invention may be readily understood I havehereinafter described constructions in which the terminals or supports,and also the incandescing conductors, are of tungsten.

Figure 1 shows an incandescent lamp pro vided with a tungsten filamentand pressed tungsten terminals. Fig. 2 is a sectional elevation of oneform of terminal. Fig. 3 is a section of a modified form of terminal.Fig. 4 is a diagrammatic representation of a plurality of incandescentconductors connected in series by a plurality of pressed terminals. Fig.5 is a detail of the joints used in the construction shown in Fig. 4.

Referring to Figs. 1 and 2, a tungsten filament 1 is connected to apressed or molded terminal or block 2 of tungsten. The latter is securedin any suitable way to the metal conductor 3, which may be of copper,and a platinum sealing wire 4 and a copper lead wire 5 complete themeans for introducing current into the tungsten filament.

In Fig. 2, I have shown the tungsten filament as connected with the.tungsten block 2 by being introduced into a cup-shaped depression in theblock and surrounded with tungsten powder 6 packed tightly around thefilament. I find that such a pint will hold the filament in place andthat the joint becomes stronger with use because of hardening orsintering of the metal powder. I

have illustrated the tungsten block 2 as screw-threaded to the copperconductor 3 but various other methods of attachment may be used. Ifdesired, I may fuse the copper into the tungsten block and thereby makea welded joint, or I may use a binding material which does notdisintegrate at the relatively low temperature of the tungsten block.

Fig. 3 shows an alternative means for connecting the filament to thelead wire, which possesses some advantageous features. In this case, thetungsten block 7 is arranged transversely of the filament 8 and ispierced with two conical holes. In one of these, a platinum lead-wire 9is introduced and then fused down at the end to completely fill theconical hole in the block and rigidly secure the lead-wire to the block.The filament 8 passes through the other hole of the block and may berigidly secured therein by fusing down a globule of platinum 10 aroundthe filament. In this construction, the block is of sufficient size andradiating power to prevent the development of an excessive temperaturetherein, and is, therefore, cool enough to prevent the vaporization ofthe platinum, even though the filament is operated at a temperature muchhigher than that at which platinum vaporizes.

In Fig. 4, I have illustrated a plurality of filaments or rods 11disposed in a zig-zag form about a suitable supporting means. I desirethis figure to be considered merely as a diagrammatic representation ofan arrangement of inoandescing conductors which might be used in a lampor in other types of electrical apparatus. I have illustrated each ofthe conductors 11 as electrically connected and supported at the bottomby metal blocks 12, and similarly connected and supported at the top byblocks 13. These blocks are supported by platinum or other rods 14carried by a-standard 15 of glass or other insulating material. It willbe apparent that these blocks may be supported in a great variety ofways and that the whole apparatus ma be variously modified and stillcome wit in the scope of In invention as defined by the claims appen edhereto.

Fig. 5 shows one good way of connecting the rods or filaments 11 to theupper and lower supporting blocks. In the lower block 12, I provide adepression filled with refractor powder 16, in which the incandescing rois embedded. If desired, a bushing 17 may be pressed down tightly on thetop of the powder to insure a good initial contact between the rod andthe block 12. I find that after the apparatus has been run for some timethe powder bakes or sinters together into a compact, somewhat dense bodyand grips the rod very tightly. A somewhat similar joint is made in theupper block 13 by excavating a cup-shaped hole 18 through which the rod11 passes and in p which' the rod is in contact with metal powder heldfirmly in place by a bushing 19.

If I use a tungsten incandescing conductor I may use tungsten blocks orterminals an a packing of tungsten powder. If I use tantalumincandescing conductors, I may make the other parts of tantalum. It willbe understood, however, that my invention embraces the use, with arefractory metal conductor, of pressed or molded terminals of the samemetal or of another refractory metal which does not chemically react onthe incandescing conductors and is otherwise stable at the temperatureof operation.

The pure metal blocks or terminals above described may be made bycompressing pure metal powder into the desired shape, but forconvenience in manufacture I sometimes add a small quantity of bindingmaterial such as glucose dissolved in water, thereby obtaining a mixturewhich is easy to mold and compress into the desired form. The additionof glucose introduces a very small amount of carbon into the mixture;and although the proportion of carbon to the metal is small,nevertheless I prefer to add to the mixture some reducible compoundwhich will subsequently combine with the carbon and yield a volatileproduct. An oxid of the refractory metal is suitable for use as thereducible compound and should be added in the proportion of about 5parts by weight when the proportion of glucose is a proximately 2 partsby weight.

The reduction of the oxid may be efiected by heating the pressed-upblocks to the temperature at which reduction occurs, or the material maybe mounted in the lamp, fur nace or other apparatus and there given apreliminary heat run before being put into regular operation.

It should be noted that when the apparatus is finished, no carbonaceousmaterial remains at the junction between the intensely hot incandescingconductor and the other parts of the electrical circuit, that theterminals are of substantially the same refrac-,

tive power as the hottest part of the apparatus and consequently willresist dismtegration at any temperature attainable in the device.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. The combination with an incandescing conductor of refractory metal,of a heat radiating terminal therefor consisting of a body of compressedrefractory metal powder.

2. The combination with a refractory conductor of pure metal, ofsupporting means therefor consisting of a block of compressed refractorypowder.

3. A terminal for a refractory conductor, consisting of metal powderconsolidated into a coherent body by pressure.

4. In an electrical apparatus, the combination with a refractoryconductor, of a less refractory conductor, and a block of compressedmetal powder electrically connect-ing said conductors.

5. A heat radiating support for a tungsten conductor consisting of acoherent body of compressed tungsten powder.

6. The combination with an incandescing conductor of refractory metal,of a heat radiating support therefor consisting of a body of compressedrefractory metal powder, and a current conductor by which current isfurnished to said incandescing conductor through said heat-radiatingsupport.

7. The combination with a refractory metal conductor, of a refractorymetal terminal therefor, and a packing of metal powder between saidconductor and said terminal.

8. In an electrical apparatus, a tungsten resistance member and a blockof compressed tungsten powder supporting said conductor and establishingan electrical connection therewith.

9. The combination with a refractory metal conductor, of means forestablishing an electrical connection therewith, said means consistingentirely of compressed refractory metal.

10. In an electrical apparatus, the combi' nation of a tungstenresistance member, a block of compressed tungsten powder serving as asupport for said member, a packing of tungsten powder between saidresistance member and said block, and a conductor establishingelectrical connection with said block.

11. In an electrical apparatus, the combination of a refractory metalresistance member and a rigid support for either end of said member,said supports each comprising a block of compressed metal powder with asocket containing the end of said resistance member packed about withdry metal powder.

12. A tungsten resistance stick held in a tungsten block by a sinteredresidue of dry powdered tungsten.

13. The combination of a resistance stick of compressed tungsten powder,rigidly mounted blocks of compressed tungsten powder engaging said stickat either end, and a packing between said stick and blocks consisting ofa .sintered residue of dry metal powder.

14. The combination of a suitable standard, a plurality of sets ofsupporting devices radiating from said standard, and a plurality offilaments arranged adjacent to said standard and carried therefrom bysaid de- 15 nection and to the longitudinal direction of 20 thefilaments by which the connection is secured to the standard. I

In witness whereof, I have hereunto set my hand this 30th day of June,1906.

AXEL O. APPELBERG. Witnesses:

EDWARD WILLIAMS; Jr., ABBA B. MARVIN, Jr.

